I am using the device they shipped me that I received yesterday and its cutting calls off at exactly 29.5 minutes. I just sent a email to support. Odd because before I hooked up this device I was using X-Lite to make calls and was on the phone 90 minutes with no problem except a slight bit of noise on the line and the person on the other end if out of state saying they heard a echo of some kind (odd since I was using a headset).